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排序方式: 共有206条查询结果,搜索用时 15 毫秒
201.
在铝基金属树脂复合结合剂中添加质量分数为0~0.4%的微量胶体石墨,研究复合结合剂的强度、硬度、微观组织及其反应结合机理。结果表明:在烧结温度为360 ℃,保温时间为5 min,保温压力为2 100 N/cm2条件下,随着胶体石墨质量分数增加,复合结合剂的密度先下降再上升随后又下降; 硬度、强度和弹性模量都是先上升再下降。在胶体石墨添加质量分数为0.2%时,复合结合剂的硬度和强度达最大值,分别为61.5 HRB和250 MPa,且复合结合剂的密度和弹性模量适中。微量胶体石墨可以和复合结合剂中的Al生成少量Al4C3,促进三维交叉网状结构形成,提高低温金属树脂复合结合剂性能。 相似文献
202.
203.
《Ceramics International》2023,49(10):15003-15014
The conventional Polymethyl methacrylate (PMMA) bone cement is not biodegradable and not bioactive to bond with the native bone and causes tissue necrosis resulting from its high exothermic polymerization. Hence, biodegradable bioactive bone cements with suitable setting time and mechanical properties should be introduced. In this study, novel bioactive bone cements containing Calcium Sulfate Hemihydrate (CSH), Bioactive Glass (BG), and Tricalcium Silicate (TSC) were developed. Firstly, CSH and BG binary system was optimized based on preliminary setting and mechanical tests. Secondly, the composite bioactive bone cements were obtained by adding different quantities of TCS to the optimized CS-BG (1.3:1 wt % ratio) system. All groups exhibited desirable handling properties, an initial setting time of lower than 15 min, injectability of greater than 85%, and controlled degradability. Moreover, they demonstrated initial compressive strength values of higher than 12 MPa, superior to trabecular bone. After 28 days of hydration, the compressive strength of the cement containing 30% TCS reached 51.04 MPa. Furthermore, the present bone cements showed favorable bioactivity and bone-bonding ability as a result of calcium carbonate and hydroxyapatite (HA) formation. Furthermore, this novel bone cement exhibited appropriate biocompatibility and mesenchymal stem cell attachment, suggesting its potential for clinical applications. 相似文献
204.
《Ceramics International》2023,49(10):15024-15033
Digital light processing (DLP) is a relatively mature ceramic additive manufacturing technology widely applied in medical bone implantation, electronic communication, and other fields. However, the size error caused by the light scattering from the complex contour can seriously affect the precision and forming quality of the printed green body. This paper studied the scattering behavior of complex structure ceramics under different exposure energies through two structural parameters: exposure width and contour shape. A formula for excess cure width is presented. The formula will be then applied to simplify the machine learning algorithms. Finally, by inverse compensation for the complex contour, we optimized some pore structures and complex shapes to greatly improve the fidelity of the structure. 相似文献
205.
《Ceramics International》2023,49(12):20456-20464
Alumina ceramics with optimized microstructures and mechanical properties were obtained by the attractive digital lighting processing (DLP) additive manufacturing methodology in the present study. A acrylate-based resin system was designed for the alumina powders with a mean particle size of 0.5 μm. The influence of oligomer on the viscosity and polymerization kinetics of the ceramic suspensions has been elaborately discussed by rheology, curing depth and photo-DSC characterizations. The results indicated that the introduction of oligomer has improved the cross-linking density of resins and decreased the critical dose of energy for resin polymerization, which contributed to a tougher ceramic-resin slice with higher dimensional accuracy. Densifying processes including debinding and high temperature sintering of the ceramic parts were conducted according to the TG-DTA characterizations, alumina ceramics with uniform microstructures and eliminated delamination or intralaminar cracks were finally obtained. The flexural strength was 471 MPa for the ceramics obtained from the resin composition containing 20 wt% oligomer, Weibull modulus for the ceramics were determined to be 17.31 by evaluating thirty all sides polished ceramics, indicating the highly uniform property of the ceramics fabricated by DLP additive manufacturing. 相似文献
206.
《Ceramics International》2023,49(20):33205-33213
High-performance SiOC(Fe) wave-absorbing ceramics, containing a large number of carbon nanowires, were successfully prepared using a combination of photopolymerization 3D printing technology and the polymer-derived ceramic pyrolysis method. By employing an optimized segmented slow heating scheme with extended holding time, the pyrolysis of SiOC(Fe) ceramics at 1000 °C facilitated the growth of carbon nanowires, Fe3C and SiO2 grains. These carbon nanowires were interlaced and interconnected within the samples, forming abundant conductive networks. This highly conducive network efficiently converted electromagnetic energy into thermal energy, effectively dissipating electromagnetic waves, and consequently enhancing the microwave absorption performance of ceramics. Moreover, this approach not only reduced ceramic cracks but also improved the dielectric loss performance of the materials, achieving a minimum reflectivity value of −35.72 dB. The SiOC(Fe) ceramics added with 5 wt% VcFe effectively enhanced the magnetic loss of the material, reduced the difference between the relative complex permeability (μr) and the relative complex dielectric constant (εr), and improved the impedance matching between the material surface and air, thereby further improving its microwave absorption performance. This resulted in an increase in the maximum effective absorption bandwidth of the material to 12.7 GHz at 5 mm. This study offers a promising solution for the preparation of ceramic matrix composite materials incorporating carbon nanowires, magnetic particles and ceramic precursors, which would be potentially valuable for radar detection and sensor applications. 相似文献